Because of the primary commercial importance of abalone among marine organisms above classified, the abalone is used as the basis for describing our invention.
Abalone, in the natural state, are fast being depleted by predators, ocean pollution and commercial harvesting to the point that there is no longer an adequate supply of this shellfish to satisfy world demand. The price of edible abalone meat has escalated seven-fold over the last ten years.
It is pertinent to the present invention that when swimming abalone larvae reach a certain stage of development, they begin to search for suitable substrates upon which to settle and change from a swimming larvae to a surface crawling animal. With a suitable substrate and other favorable conditions, the young gastropod undergoes metamorphosis and rapid growth. Our copending application Ser. No. 955,944, filed Oct. 30, 1978, is directed to procedures for optimizing the settlement of abalone larvae and the rapid growth of the juvenile animals.
In nature and in culture, the larvae select suitable surfaces upon which to settle by temporarily ceasing to manipulate their swimming mechanism, thereby allowing gravity to gently pull their body to the ocean floor. When a larva settles upon a surface on the sea floor, it extends a muscular foot and attempts to attach to the solid material upon which it has landed. As described in the aforementioned application Ser. No. 955,944, this settlement process may take some time before the larva finds the surface suitable to it. In nature, and therefore also in culturing operations, abalone usually find upward facing surfaces of an approximate horizontal orientation for settlement, yet when they grow in size they often prefer to rest on vertical and downward facing horizontal surfaces when they are not foraging for food. In addition, young abalone seek out corners for protection when not actively feeding. Recognizing the needs of a young abalone and the procedures necessary for the successful mariculture thereof, we have developed a specially designed tank for this purpose.